User terminal and radio communication method

ABSTRACT

A user terminal according to one aspect of the present disclosure includes: a reception section that receives information related to a beam selection index; and a control section that selects a beam based on an index indicated by the information. According to one aspect of the present disclosure, it is possible to appropriately select a beam and report the beam.

TECHNICAL FIELD

The present disclosure relates to a user terminal and a radiocommunication method of a next-generation mobile communication system.

BACKGROUND ART

In Universal Mobile Telecommunications System (UMTS) networks, for thepurpose of higher data rates and lower latency, Long Term Evolution(LTE) has been specified (Non-Patent Literature 1). Furthermore, for thepurpose of a larger capacity and higher sophistication than those of LTE(LTE Rel. 8 and 9), LTE-Advanced (LTE-A and LTE Rel. 10, 11, 12 and 13)has been specified.

LTE successor systems (also referred to as, for example, Future RadioAccess (FRA), the 5th generation mobile communication system (5G),5G+(plus), New Radio (NR), New radio access (NX), Future generationradio access (FX) or LTE Rel. 14, 15 or subsequent releases) are alsostudied.

In legacy LTE systems (e.g., LTE Rel. 8 to 13), a user terminal (UE:User Equipment) periodically and/or aperiodically transmits ChannelState Information (CSI) to a base station. The UE transmits the CSI byusing an uplink control channel (PUCCH: Physical Uplink Control Channel)and/or an uplink shared channel (PUSCH: Physical Uplink Shared Channel).

CITATION LIST Non-Patent Literature

-   Non-Patent Literature 1: 3GPP TS 36.300 V8.12.0 “Evolved Universal    Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial    Radio Access Network (E-UTRAN); Overall description; Stage 2    (Release 8)”, April 2010

SUMMARY OF INVENTION Technical Problem

A Beam Management (BM) method has been studied for a future radiocommunication system (e.g., NR). According to this beam management, itis studied to perform beam selection based on L1-RSRP (Reference SignalReceived Power (RSRP) in a physical layer (layer 1)) reported by a UE.

Furthermore, it is also studied to use a beam measurement result (suchas interference measurement) other than the L1-RSRP. However, study on aspecific notification method for the UE for this new beamselection/reporting does not advance yet. When this selection/reportingcannot be performed, it is not possible to appropriately perform beamselection, and there is a risk that a communication throughput lowers.

It is therefore one of objects of the present disclosure to provide auser terminal and a radio communication method that can appropriatelyselect a beam and report the beam.

Solution to Problem

A user terminal according to one aspect of the present disclosureincludes: a reception section that receives information related to abeam selection index; and a control section that selects a beam based onan index indicated by the information.

Advantageous Effects of Invention

According to one aspect of the present disclosure, it is possible toappropriately select a beam and report the beam.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an excerpt of an RRC information element“CSI-ReportConfig”.

FIGS. 2A and 2B are diagrams illustrating one example of an RRCparameter that indicates index information.

FIGS. 3A and 3B are diagrams illustrating another example of the RRCparameter that indicates the index information.

FIG. 4 is a diagram illustrating one example of beam selection.

FIG. 5 is a diagram illustrating one example of a report quantity forreporting at least one of RSRP and an SINR.

FIG. 6 is a diagram illustrating another example of the report quantityfor reporting at least one of the RSRP and the SINR.

FIG. 7 is a diagram illustrating one example of a schematicconfiguration of a radio communication system according to oneembodiment.

FIG. 8 is a diagram illustrating one example of an overall configurationof a base station according to the one embodiment.

FIG. 9 is a diagram illustrating one example of a function configurationof the base station according to the one embodiment.

FIG. 10 is a diagram illustrating one example of an overallconfiguration of a user terminal according to the one embodiment.

FIG. 11 is a diagram illustrating one example of a functionconfiguration of the user terminal according to the one embodiment.

FIG. 12 is a diagram illustrating one example of hardware configurationsof the base station and the user terminal according to the oneembodiment.

DESCRIPTION OF EMBODIMENTS

According to NR, a UE measures a channel state by using a givenreference signal (or a resource for the given reference signal), andfeeds back (reports) Channel State Information (CSI) to a base station.

The UE may measure the channel state by using a Channel StateInformation Reference Signal (CSI-RS), a Synchronization Signal/PhysicalBroadcast Channel (SS/PBCH) block, a Synchronization Signal (SS) or aDeModulation Reference Signal (DMRS).

The CSI-RS resource may include at least one of a Non Zero Power (NZP)CSI-RS and CSI-Interference Management (IM). The SS/PBCH block is ablock that includes a synchronization signal (e.g., a PrimarySynchronization Signal (PSS) or a Secondary Synchronization Signal(SSS)) and a PBCH (and a corresponding DMRS), and may be referred to asan SS Block (SSB).

In addition, the CSI may include at least one of a Channel QualityIndicator (CQI), a Precoding Matrix Indicator (PMI), a CSI-RS ResourceIndicator (CRI), an SS/PBCH Block Resource Indicator (SSBRI), a LayerIndicator (LI), a Rank Indicator (RI), Layer 1 Reference Signal ReceivedPower (L1-RSRP), L1-Reference Signal Received Quality (RSRQ), anL1-Signal to Interference plus Noise Ratio (SINR), and an L1-Signal toNoise Ratio (SNR).

The CSI may include a plurality of parts. A first part (CSI part 1) ofthe CSI may include information (e.g., RI) of a relatively small numberof bits. A second part (CSI part 2) of the CSI may include information(e.g., CQI) of a relatively large number of bits such as informationdetermined based on the CSI part 1.

As a CSI feedback method, (1) a Periodic CSI (P-CSI) reporting, (2) anAperiodic CSI (A-CSI) reporting and (3) a Semi-Permanent(semi-continuous or Semi-Persistent) CSI reporting (SP-CSI) are studied.

The UE may be notified of information (that may be referred to as CSIreporting configuration information) related to a CSI reporting by usinga higher layer signaling, a physical layer signaling (e.g., DownlinkControl Information (DCI)) or a combination of these signalings. The CSIreporting configuration information may be configured by using, forexample, an RRC information element “CSI-ReportConfig”.

In this regard, the higher layer signaling may be one or a combinationof, for example, a Radio Resource Control (RRC) signaling, a MediumAccess Control (MAC) signaling and broadcast information.

The MAC signaling may use, for example, an MAC Control Element (MAC CE)or an MAC Protocol Data Unit (PDU). The broadcast information may be,for example, a Master Information Block (MIB), a System InformationBlock (SIB), Remaining Minimum System Information (RMSI), or OtherSystem Information (OSI).

CSI reporting configuration information may include, for example,information related to a report periodicity and an offset, and thesegiven periodicity and offset may be expressed in a given time unit (suchas a slot unit, a subframe unit or a symbol unit). The CSI reportingconfiguration information may include a configuration ID(CSI-ReportConfigId), and parameters such as a CSI reporting method type(SP-CSI or not) and the report periodicity may be specified based on theconfiguration ID. The CSI reporting configuration information mayinclude information (CSI-ResourceConfigId) that indicates which CSImeasured by using which signal (or a resource for which signal) toreport.

(Beam Management)

A Beam Management (BM) method has been studied for Rel-15 NR so far. Itis studied for the beam management to perform beam selection based onL1-RSRP reported by the UE. Changing (switching) a beam of a certainsignal/channel may correspond to changing a Transmission ConfigurationIndication state (TCI state) of the certain signal/channel.

In addition, a beam selected by beam selection may be a transmissionbeam (Tx beam), or may be a reception beam (Rx beam). Furthermore, thebeam selected by beam selection may be a beam of the UE, or may be abeam of the base station.

The UE may report (transmit) a measurement result for beam management byusing a PUCCH or a PUSCH. The measurement result may be CSI including atleast one of L1-RSRP, L1-RSRQ, an L1-SINR and an L1-SNR. Furthermore,the measurement result may be referred to as beam measurement, a beammeasurement result, a beam report or a beam measurement report.

CSI measurement for a beam report may include interference measurement.The UE may measure channel quality or an interference by using aresource for CSI measurement, and derive the beam report. The resourcefor CSI measurement may be at least one of, for example, an SS/PBCHblock resource, a CSI-RS resource and other reference signal resources.Configuration information of the CSI measurement report may beconfigured to the UE by using a higher layer signaling.

The beam report may include a result of at least one of channel qualitymeasurement and interference measurement. The channel qualitymeasurement result may include, for example, L1-RSRP. The interferencemeasurement result may include the L1-SINR, the L1-SNR, the L1-RSRQ andother indices related to the interference (e.g., arbitrary indices otherthan L1-RSRP).

In addition, a CSI measurement resource for beam management may bereferred to as a beam measurement resource. Furthermore, a CSImeasurement target signal/channel may be referred to as a beammeasurement signal. Furthermore, CSI measurement/reporting may be readas at least one of measurement/reporting for beam management, beammeasurement/reporting and radio link quality measurement/reporting.

CSI reporting configuration information that takes beam management ofcurrent NR into account will be described with reference to FIG. 1. FIG.1 illustrates an excerpt of the RRC information element“CSI-ReportConfig”. FIG. 1 is drawn by using an Abstract Syntax NotationOne (ASN.1) notation (the same applies to mentioned-below FIGS. 2, 3, 5and 6, too).

The CSI reporting configuration information (CSI-ReportConfig) mayinclude a “report quantity” (that may be expressed as an RRC parameter“reportQuantity”) that is information of a parameter to be reported. Thereport quality is defined as a type of an ASN. 1 object that is“choice”. Hence, one of parameters (such as cri-RSRP and ssb-Index-RSRP)defined as the report quantity is configured.

The UE for which a higher layer parameter (e.g., RRC parameter“groupBasedBeamReporting”) included in the CSI reporting configurationinformation has been configured to enabled may include a plurality ofbeam measurement resource IDs (e.g., SSB RIs or CRIs) and a plurality ofmeasurement results (e.g., L1-RSRP) associated with these beammeasurement resource IDs in a beam report for each report configuration.

The UE to which the number of report target RS resources that is one ormore has been configured by a higher layer parameter (e.g., RRCparameter “nrofReportedRS”) included in the CSI reporting configurationinformation may include one or more beam measurement resource IDs andone or more measurement results (e.g., L1-RSRP) associated with thesebeam measurement resource IDs in a beam report for each reportconfiguration.

By the way, according to Rel-15 NR, cri-RSRP and ssb-Index-RSRP amongreport quantities relate to beam management. The UE to which thecri-RSRP has been configured reports a CRI and L1-RSRP associated withthe CRI. The UE to which the ssb-Index-RSRP has been configured reportsan SSBRI and L1-RSRP associated with the CRI.

However, according to NR that has been studied so far, it is onlypossible to perform beam selection based on only the L1-RSRP.Furthermore, it is not possible to make a configuration for including aninterference report (a report of, for example, L1-RSRQ) in a beamreport. When beam selection and reporting relate to only the L1-RSRP, itis not possible to appropriately perform beam selection, and thereforethere is a risk that a communication throughput lowers.

Hence, the inventors of the present invention have conceived a CSIreporting configuration for appropriately selecting a beam and reportingthe beam.

Embodiments according to the present disclosure will be described indetail below with reference to the drawings. A radio communicationmethod according to each embodiment may be each applied alone or may beapplied in combination.

In the present disclosure, an “interference” may be read as an SINR, anSNR, RSRQ, other indices related to the interference (e.g., arbitraryindices other than L1-RSRP) and interference power. Furthermore,“L1-RSRQ/SINR” may be read as at least one of L1-RSRQ and an L1-SINR.

(Radio Communication Method)

First Embodiment

According to the first embodiment, a UE may perform beam selection basedon only L1-RSRP, may perform beam selection based on only L1-RSRQ/SINR,or may perform beam selection based on both of the L1-RSRP andL1-RSRQ/SINR.

Information related to beam selection criteria (indices) may beconfigured to the UE by using a higher layer signaling. The informationmay be referred to as index information below.

The index information may be defined by a new RRC parameter (or an RRCinformation element). The index information may be defined by, forexample, an RRC parameter “beamselectioncriteria (orbeamSelectionCriteria)”. The index information may be included in CSIreporting configuration information (CSI-ReportConfig), and notified tothe UE, or may be notified separately from the CSI reportingconfiguration information.

FIGS. 2A and 2B are diagrams illustrating one example of the RRCparameter that indicates the index information. The UE may use, forexample, one of followings as the beam selection index based on a valueof the index information in FIGS. 2A and 28:

L1-RSRP,

L1-RSRQ,

An L1-SINR,

L1-RSRP and L1-RSRQ, and

L1-RSRP and an L1-SINR.

FIG. 2A illustrates one example of a definition in a case where CHOICEaccording to ASN.1 notation is used. In a case of CHOICE, only one oflisted values can be selected, and therefore it is necessary to includesuch a field when a plurality of indices are indicated. When, forexample, L1-RSRP and L1-RSRQ are indicated, “L1-RSRP-RSRQ” is selected.

FIG. 2B illustrates one example of a definition in a case where SEQUENCEaccording to the ASN.1 notation is used. In a case of SEQUENCE, one or aplurality of listed values can be selected (“OPTIONAL” means notindispensable), and therefore a plurality of dedicated fields only needto be included when a plurality of indices are indicated. When, forexample, the L1-RSRP and the L1-RSRQ are indicated, “L1-RSRP” and“L1-RSRQ” are selected.

FIGS. 3A and 3B are diagrams illustrating another example of the RRCparameter that indicates the index information. The UE may use, forexample, one of followings as a beam selection index based on values ofthe index information in FIGS. 3A and 38:

csi-RSRP,

ssb-RSRP,

csi-RSRQ,

ssb-RSRQ,

A csi-SINR,

An ssb-SINR,

csi-RSRP and csi-RSRQ,

ssb-RSRP and ssb-RSRQ,

csi-RSRP and a csi-SINR, and

ssb-RSRP and an ssb-SINR.

FIGS. 3A and 3B respectively illustrate corresponding indices thatexpress the indices in FIGS. 2A and 2B as items of specific measurementcontents. This is because, as L1-RSRP/RSRQ/SINR, csi-RSRP/RSRQ/SINR thatare measurement values based on a CSI-RS, or ssb-RSRP/RSRQ/SINR that aremeasurement values based on an SSB (e.g., an SSS in an SSB and/or aDMRS) are actually used.

In addition, even when the CSI reporting configuration informationincludes the index information, the report quantity including the CSIreporting configuration information may instruct a measurement resultdifferent from the index indicated by the index information.

Furthermore, when the CSI reporting configuration information does notinclude the index information or the index information is not specified,the UE may determine the beam selection criteria (indices) based on areport quantity (“reportQuantity”) included in the CSI reportingconfiguration information.

When, for example, the report quantity configured to the UE instructsreporting of the csi-SINR, the UE may perform beam selection based onthe L1-SINR (csi-SINR), and report the csi-SINR of a selected beam.Candidate values of the report quantity will be described in the secondembodiment.

When a combination of the L1-RSRP and the L1-RSRQ/SINR is configured asthe beam selection index to the UE, and when a group-based beam reportis configured to disabled by a higher layer signaling, the UE mayinclude different nrofReportedRS CRIs/SSBRIs in one report for eachreport configuration to report.

The UE may first determine M best candidate RSs (candidate beams) basedon the L1-RSRP. In this regard, a value of M may be configured by ahigher layer signaling, or may be defined by a specification. Inaddition, M may be assumed as a value equal to or more thannrofReportedRS. Subsequently, the UE may determine nrofReportedRSmeasurement results to report from a result of the determined Mcandidate RSs based on the L1-RSRQ/SINR.

The UE may determine the above M best candidate RSs according to one offollowings:

(1) The M best candidate RSs in order of larger values,(2) The M best candidate RSs within a given range (gap) (e.g., X dB)from L1-RSRP of the largest value, and(3) The M best candidate RSs larger than a given threshold (e.g., YdBm).

The UE may determine the above nrofReportedRS measurement resultsaccording to one of followings:

(A) The nrofReportedRS measurement results in order of larger values,(B) The nrofReportedRS measurement results within a given range (gap)from L1-RSRP of the largest value, and(C) The nrofReportedRS measurement results larger than a giventhreshold.

These given range and given threshold may be configured to the UE byusing a higher layer signaling, a physical layer signaling or acombination of these signalings.

Conversely, the UE may first determine the M best candidate RSs based onthe L1-RSRQ/SINR, and subsequently determine the nrofReportedRSmeasurement results to report based on L1-RSRP.

A case where the UE determines candidate RSs by using one of above (1)to (3), and then determines a report target by using above (A) will bedescribed with reference to FIG. 4. FIG. 4 is a diagram illustrating oneexample of beam selection. This example assumes that the UE isconfigured to measure eight transmission beams (Tx beams #1 to #8)transmitted from a base station (TXRU 1). Furthermore, the UE measuresthese transmission beams by using two reception beams (Rx beams #1 and#2).

In addition, M=4 and nrofReportedRS=2 are configured. Furthermore, abovegiven range=3 dB and above given threshold=−60 dBm are assumed.

In a case based on above (1), the UE may first select four transmissionbeams in order of larger values from L1-RSRP that is a combination ofall transmission beams and reception beams. A measurement result of{transmission beam, reception beam}={4, 1} corresponds to the bestL1-RSRP at −56 dBm. Thus, the UE first selects four sets of{transmission beam, reception beam}={4, 1}, {1, 1}, {2, 1} and {5, 2}.

FIG. 4 illustrates L1-RSRQ of the four sets. A maximum value of thesesets is 30 dB of {transmission beam, reception beam}={1, 1}. Thus, theUE determines two sets of {transmission beam, reception beam}={1, 1} and{5, 2} as report targets.

In a case based on above (2), L1-RSRP of {transmission beam, receptionbeam}={5, 2} is −60 dBm, and is not included within the above givenrange from best −56 dBm.

In this case, the UE first selects three sets of {transmission beam,reception beam}={4, 1}, {1, 1} and {2, 1}. Subsequently, the UEdetermines the two sets of {transmission beam, reception beam}={1, 1}and {2, 1} as report targets.

In a case based on above (3), the UE first selects four sets of{transmission beam, reception beam}={4, 1}, {1, 1}, {2, 1} and {5, 2}.Subsequently, the UE determines two sets of {transmission beam,reception beam}={1, 1} and {5, 2} as report targets.

According to the above-described first embodiment, the UE canappropriately determine the beam selection criteria, and perform beamselection.

Second Embodiment

The second embodiment relates to a report quantity for reporting atleast one of RSRQ and an SINR.

The report quantity may be a parameter expanded from a legacy RRCparameter “reportQuantity” or may be expressed as a new RRC parameter.The new RRC parameter may be included in CSI reporting configurationinformation (CSI-ReportConfig) and notified to a UE.

FIG. 5 is a diagram illustrating one example of a report quantity forreporting at least one of RSRQ and an SINR. The report quantity is aparameter expanded from the legacy RRC parameter “reportQuantity”.

For example, one of followings can be indicated as a report target byusing the report quantity:

csi-RSRQ (when “cri-RSRQ” is configured),

ssb-RSRQ (when “ssb-Index-RSRQ” is configured),

A csi-SINR (when “cri-SINR” is configured),

An ssb-SINR (when “ssb-Index-SINR” is configured),

csi-RSRP and csi-RSRQ (when “cri-RSRP-RSRQ” is configured),

ssb-RSRP and ssb-RSRQ (when “ssb-Index-RSRP-RSRQ” is configured),

csi-RSRP and a csi-SINR (when “cri-RSRP-SINR” is configured), and

ssb-RSRP and an ssb-SINR (when “ssb-Index-RSRP-SINR” is configured).

When, for example, “cri-RSRQ” is configured as the report quantity, theUE may report the csi-RSRQ and CRI associated with the csi-RSRQ.Furthermore, when “ssb-Index-RSRP-SINR” is configured as the reportquantity, the UE may report the ssb-RSRP, the ssb-SINR and an SSBRIassociated with the ssb-RSRP and the ssb-SINR.

In addition, the UE may include the CRI associated with a measurementresult in a report including the measurement report that starts from“csi-”. In addition, the UE may include the SSBRI associated with ameasurement result in a report including the measurement report thatstarts from “ssb-”.

Furthermore, in the present disclosure, names that start from “cri-”such “cri-RSRQ” and “cri-RSRP-SINR” may be read as names that start from“csi-” such as “csi-RSRQ” and “csi-RSRP-SINR”.

FIG. 6 is a diagram illustrating another example of the report quantityfor reporting at least one of the RSRQ and the SINR. The report quantityis configured by a new RRC parameter “reportQuantity-r16”. The reporttarget that can be indicated may be similar to the report targetdescribed with reference to FIG. 5.

This parameter may be notified to the UE that complies with, forexample, Rel-16 NR. When “reportQuantity-r16” is configured to the UE,the UE may ignore “reportQuantity”. The legacy RRC parameter“reportQuantity” may be configured to an Rel-15 UE. The Rel-15 UE mayignore a configuration of “reportQuantity-r16”. By so doing, it ispossible to reserve backward compatibility of a specification.

When a report quantity for which at least one of the csi-RSRQ, thessb-RSRQ, the csi-SINR and the ssb-SINR is configured as the reporttarget is configured to the UE, the UE may assume at least one offollowings:

To perform low latency beam selection (or measurement or report),

To perform low overhead beam selection (or measurement or report),

To perform beam failure recovery in a secondary cell,

To use an interference measurement result (e.g., RSRQ or an SINR) forbeam failure recovery,

To use an interference measurement result (e.g., RSRQ or an SINR) forbeam selection, and

To include an interference measurement result (e.g., RSRQ or an SINR) ina beam report.

In addition, low latency beam selection may be referred to as fast beamselection, beam selection w/o TCI state, a beam selection type II or aTCI state indication type 2.

Furthermore, low overhead beam selection may be, for example, a methodfor skipping reporting a beam report under a given condition.

In addition, the UE may transmit, to a base station, UE capabilityinformation related to whether or not at least one of the RSRQ and theSINR can be reported. The base station may configure the report quantitydescribed in the second embodiment to the UE that has the UE capabilityinformation.

Furthermore, the UE to which the number of report target RS resourcesthat is two or more has been configured by a higher layer parameter(e.g., RRC parameter “nrofReportedRS”) included in the CSI reportingconfiguration information may report L1-RSRP or L1-RSRQ/SINR associatedwith a certain RS in a form of a difference from maximum L1-RSRP orL1-RSRQ/SINR.

According to the above-described second embodiment, the UE canappropriately determine beam report targets.

<Others>

The base station may perform control for using a beam (e.g.,transmission beam) associated with a report reported from the UE, or mayperform control for determining a beam used based on a beam associatedwith a reported report.

Even when performing beam selection based on only L1-RSRP, the UE mayreport L1-RSRQ/SINR, too, in addition to L1-RSRP of the selected beam.By so doing, it is possible to provide a decision basis for beamdetermination of the base station.

(Radio Communication System)

The configuration of the radio communication system according to oneembodiment of the present disclosure will be described below. This radiocommunication system uses one or a combination of the radiocommunication method according to each of the above embodiments of thepresent disclosure to perform communication.

FIG. 7 is a diagram illustrating one example of a schematicconfiguration of the radio communication system according to the oneembodiment. A radio communication system 1 can apply at least one ofCarrier Aggregation (CA) and Dual Connectivity (DC) that aggregates aplurality of base frequency blocks (component carriers) whose 1 unit isa system bandwidth (e.g., 20 MHz).

In this regard, the radio communication system 1 may be referred to asLong Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B),SUPER 3G, IMT-Advanced, the 4th generation mobile communication system(4G), the 5th generation mobile communication system (5G), New Radio(NR), Future Radio Access (FRA) and the New Radio Access Technology(New-RAT), or a system that realizes these techniques.

The radio communication system 1 includes a base station 11 that forms amacro cell C1 of a relatively wide coverage, and base stations 12 (12 ato 12 c) that are located in the macro cell C1 and form small cells C2narrower than the macro cell C1. Furthermore, a user terminal 20 islocated in the macro cell C1 and each small cell C2. An arrangement andthe numbers of respective cells and the user terminals 20 are notlimited to the aspect illustrated in FIG. 7.

The user terminal 20 can connect with both of the base station 11 andthe base stations 12. The user terminal 20 is assumed to concurrentlyuse the macro cell C1 and the small cells C2 by using CA or DC.Furthermore, the user terminal 20 can apply CA or DC by using aplurality of cells (CCs).

The user terminal 20 and the base station 11 can communicate by using acarrier (also referred to as a legacy carrier) of a narrow bandwidth ina relatively low frequency band (e.g., 2 GHz). On the other hand, theuser terminal 20 and each base station 12 may use a carrier of a widebandwidth in a relatively high frequency band (e.g., 3.5 GHz or 5 GHz)or may use the same carrier as that used between the user terminal 20and the base station 11. In this regard, a configuration of thefrequency band used by each base station is not limited to this.

Furthermore, the user terminal 20 can perform communication by using atleast one of Time Division Duplex (TDD) and Frequency Division Duplex(FDD) in each cell. Furthermore, each cell (carrier) may be applied asingle numerology or may be applied a plurality of differentnumerologies.

The numerology may be a communication parameter to be applied to atleast one of transmission and reception of a certain signal or channel,and may indicate at least one of, for example, a subcarrier spacing, abandwidth, a symbol length, a cyclic prefix length, a subframe length, aTTI length, the number of symbols per TTI, a radio frame configuration,specific filtering processing performed by a transceiver in a frequencydomain, and specific windowing processing performed by the transceiverin a time domain.

For example, a case where at least one of subcarrier spacings ofconstituent OFDM symbols and the number of OFDM symbols are different ona certain physical channel may be read as that numerologies aredifferent.

The base station 11 and each base station 12 (or the two base stations12) may be connected by way of wired connection (e.g., optical fiberscompliant with a Common Public Radio Interface (CPRI) or an X2interface) or radio connection.

The base station 11 and each base station 12 are each connected with ahigher station apparatus 30 and connected with a core network 40 via thehigher station apparatus 30. In this regard, the higher stationapparatus 30 includes, for example, an access gateway apparatus, a RadioNetwork Controller (RNC) and a Mobility Management Entity (MME), yet isnot limited to these. Furthermore, each base station 12 may be connectedwith the higher station apparatus 30 via the base station 11.

In this regard, the base station 11 is a base station that has arelatively wide coverage, and may be referred to as a macro basestation, an aggregate node, an eNodeB (eNB) or a transmission/receptionpoint. Furthermore, each base station 12 is a base station that has alocal coverage, and may be referred to as a small base station, a microbase station, a pico base station, a femto base station, a Home eNodeB(HeNB), a Remote Radio Head (RRH) or a transmission/reception point. Thebase stations 11 and 12 will be collectively referred to as a basestation 10 below when not distinguished.

Each user terminal 20 is a terminal that supports various communicationschemes such as LTE, LTE-A and 5G, and may include not only a mobilecommunication terminal (mobile station) but also a fixed communicationterminal (fixed station).

The radio communication system 1 applies Orthogonal Frequency-DivisionMultiple Access (OFDMA) to downlink and applies at least one of SingleCarrier-Frequency Division Multiple Access (SC-FDMA) and OFDMA to uplinkas radio access schemes.

OFDMA is a multicarrier transmission scheme that divides a frequencyband into a plurality of narrow frequency bands (subcarriers) and mapsdata on each subcarrier to perform communication. SC-FDMA is a singlecarrier transmission scheme that divides a system bandwidth into bandsincluding one or contiguous resource blocks per terminal and causes aplurality of terminals to use respectively different bands to reduce aninter-terminal interference. In this regard, uplink and downlink radioaccess schemes are not limited to a combination of these schemes, andother radio access schemes may be used.

The radio communication system 1 uses a downlink shared channel (PDSCH:Physical Downlink Shared Channel) shared by each user terminal 20, abroadcast channel (PBCH: Physical Broadcast Channel) and a downlinkcontrol channel as downlink channels. User data, higher layer controlinformation and a System Information Block (SIB) are conveyed on thePDSCH. Furthermore, a Master Information Block (MIB) is conveyed on thePBCH.

The downlink control channel includes a Physical Downlink ControlChannel (PDCCH), an Enhanced Physical Downlink Control Channel (EPDCCH),a Physical Control Format Indicator Channel (PCFICH), and a PhysicalHybrid-ARQ Indicator Channel (PHICH). Downlink Control Information (DCI)including scheduling information of at least one of the PDSCH and thePUSCH is conveyed on the PDCCH.

In addition, DCI for scheduling DL data reception may be referred to asa DL assignment, and DCI for scheduling UL data transmission may bereferred to as a UL grant.

The number of OFDM symbols used for the PDCCH is conveyed on the PCFICH.Transmission acknowledgement information (also referred to as, forexample, retransmission control information, HARQ-ACK or ACK/NACK) of aHybrid Automatic Repeat reQuest (HARQ) for the PUSCH may be conveyed onthe PHICH. The EPDCCH is subjected to frequency division multiplexingwith the PDSCH (downlink shared data channel) and is used to convey DCIsimilar to the PDCCH.

The radio communication system 1 uses an uplink shared channel (PUSCH:Physical Uplink Shared Channel) shared by each user terminal 20, anuplink control channel (PUCCH: Physical Uplink Control Channel), and arandom access channel (PRACH: Physical Random Access Channel) as uplinkchannels. User data and higher layer control information are conveyed onthe PUSCH. Furthermore, downlink radio quality information (CQI: ChannelQuality Indicator), transmission acknowledgement information and aScheduling Request (SR) are conveyed on the PUCCH. A random accesspreamble for establishing connection with a cell is conveyed on thePRACH.

The radio communication system 1 conveys a Cell-specific ReferenceSignal (CRS), a Channel State Information-Reference Signal (CSI-RS), aDeModulation Reference Signal (DMRS) and a Positioning Reference Signal(PRS) as downlink reference signals. Furthermore, the radiocommunication system 1 conveys a Sounding Reference Signal (SRS) and aDeModulation Reference Signal (DMRS) as uplink reference signals. Inthis regard, the DMRS may be referred to as a user terminal-specificreference signal (UE-specific reference signal). Furthermore, areference signal to be conveyed is not limited to these.

(Base Station)

FIG. 8 is a diagram illustrating one example of an overall configurationof the base station according to the one embodiment. The base station 10includes pluralities of transmission/reception antennas 101, amplifyingsections 102 and transmitting/receiving sections 103, a baseband signalprocessing section 104, a call processing section 105 and acommunication path interface 106. In this regard, the base station 10only needs to be configured to include one or more of each of thetransmission/reception antennas 101, the amplifying sections 102 and thetransmitting/receiving sections 103.

User data transmitted from the base station 10 to the user terminal 20on downlink is input from the higher station apparatus 30 to thebaseband signal processing section 104 via the communication pathinterface 106.

The baseband signal processing section 104 performs processing of aPacket Data Convergence Protocol (PDCP) layer, segmentation andconcatenation of the user data, transmission processing of a Radio LinkControl (RLC) layer such as RLC retransmission control, Medium AccessControl (MAC) retransmission control (e.g., HARQ transmissionprocessing), and transmission processing such as scheduling,transmission format selection, channel coding, Inverse Fast FourierTransform (IFFT) processing, and precoding processing on the user data,and transfers the user data to each transmitting/receiving section 103.Furthermore, the baseband signal processing section 104 performstransmission processing such as channel coding and inverse fast Fouriertransform on a downlink control signal, too, and transfers the downlinkcontrol signal to each transmitting/receiving section 103.

Each transmitting/receiving section 103 converts a baseband signalprecoded and output per antenna from the baseband signal processingsection 104 into a radio frequency range, and transmits a radiofrequency signal. The radio frequency signal subjected to frequencyconversion by each transmitting/receiving section 103 is amplified byeach amplifying section 102, and is transmitted from eachtransmission/reception antenna 101. The transmitting/receiving sections103 can be composed of transmitters/receivers, transmission/receptioncircuits or transmission/reception apparatuses described based on acommon knowledge in a technical field according to the presentdisclosure. In this regard, the transmitting/receiving sections 103 maybe composed as an integrated transmitting/receiving section or may becomposed of transmission sections and reception sections.

Meanwhile, each amplifying section 102 amplifies a radio frequencysignal received by each transmission/reception antenna 101 as an uplinksignal. Each transmitting/receiving section 103 receives the uplinksignal amplified by each amplifying section 102. Eachtransmitting/receiving section 103 performs frequency conversion on thereceived signal into a baseband signal, and outputs the baseband signalto the baseband signal processing section 104.

The baseband signal processing section 104 performs Fast FourierTransform (FFT) processing, Inverse Discrete Fourier Transform (IDFT)processing, error correcting decoding, MAC retransmission controlreception processing, and reception processing of an RLC layer and aPDCP layer on user data included in the input uplink signal, andtransfers the user data to the higher station apparatus 30 via thecommunication path interface 106. The call processing section 105performs call processing (such as configuration and release) of acommunication channel, state management of the base station 10 and radioresource management.

The communication path interface 106 transmits and receives signals toand from the higher station apparatus 30 via a given interface.Furthermore, the communication path interface 106 may transmit andreceive (backhaul signaling) signals to and from the another basestation 10 via an inter-base station interface (e.g., optical fiberscompliant with the Common Public Radio Interface (CPRI) or the X2interface).

FIG. 9 is a diagram illustrating one example of a function configurationof the base station according to the one embodiment. In addition, thisexample mainly illustrates function blocks of characteristic portionsaccording to the present embodiment, and assumes that the base station10 includes other function blocks, too, that are necessary for radiocommunication.

The baseband signal processing section 104 includes at least a controlsection (scheduler) 301, a transmission signal generating section 302, amapping section 303, a received signal processing section 304 and ameasurement section 305. In addition, these components only need to beincluded in the base station 10, and part or all of the components maynot be included in the baseband signal processing section 104.

The control section (scheduler) 301 controls the entire base station 10.The control section 301 can be composed of a controller, a controlcircuit or a control apparatus described based on the common knowledgein the technical field according to the present disclosure.

The control section 301 controls, for example, signal generation of thetransmission signal generating section 302 and signal allocation of themapping section 303. Furthermore, the control section 301 controlssignal reception processing of the received signal processing section304 and signal measurement of the measurement section 305.

The control section 301 controls scheduling (e.g., resource allocation)of system information, a downlink data signal (e.g., a signal that istransmitted by using a downlink shared channel), and a downlink controlsignal (e.g., a signal that is transmitted by using a downlink controlchannel). Furthermore, the control section 301 controls generation of adownlink control signal and a downlink data signal based on a resultobtained by deciding whether or not it is necessary to performretransmission control on an uplink data signal.

The control section 301 controls scheduling of synchronization signals(e.g., a Primary Synchronization Signal (PSS)/a SecondarySynchronization Signal (SSS)) and downlink reference signals (e.g., aCRS, a CSI-RS and a DMRS).

The control section 301 controls scheduling of an uplink data signal(e.g., a signal that is transmitted by using an uplink shared channel),an uplink control signal (e.g., a signal that is transmitted by using anuplink control channel), a random access preamble and an uplinkreference signal.

The transmission signal generating section 302 generates a downlinksignal (such as a downlink control signal, a downlink data signal or adownlink reference signal) based on an instruction from the controlsection 301, and outputs the downlink signal to the mapping section 303.The transmission signal generating section 302 can be composed of asignal generator, a signal generating circuit or a signal generatingapparatus described based on the common knowledge in the technical fieldaccording to the present disclosure.

The transmission signal generating section 302 generates, for example,at least one of a DL assignment for giving notification of downlink dataallocation information, and a UL grant for giving notification of uplinkdata allocation information based on the instruction from the controlsection 301. The DL assignment and the UL grant are both DCI, andconform to a DCI format. Furthermore, the transmission signal generatingsection 302 performs encoding processing and modulation processing onthe downlink data signal according to a code rate and a modulationscheme determined based on Channel State Information (CSI) from eachuser terminal 20.

The mapping section 303 maps the downlink signal generated by thetransmission signal generating section 302, on given radio resourcesbased on the instruction from the control section 301, and outputs thedownlink signal to each transmitting/receiving section 103. The mappingsection 303 can be composed of a mapper, a mapping circuit or a mappingapparatus described based on the common knowledge in the technical fieldaccording to the present disclosure.

The received signal processing section 304 performs reception processing(e.g., demapping, demodulation and decoding) on a received signal inputfrom each transmitting/receiving section 103. In this regard, thereceived signal is, for example, an uplink signal (such as an uplinkcontrol signal, an uplink data signal or an uplink reference signal)transmitted from the user terminal 20. The received signal processingsection 304 can be composed of a signal processor, a signal processingcircuit or a signal processing apparatus described based on the commonknowledge in the technical field according to the present disclosure.

The received signal processing section 304 outputs information decodedby the reception processing to the control section 301. When, forexample, receiving the PUCCH including HARQ-ACK, the received signalprocessing section 304 outputs the HARQ-ACK to the control section 301.Furthermore, the received signal processing section 304 outputs at leastone of the received signal and the signal after the reception processingto the measurement section 305.

The measurement section 305 performs measurement related to the receivedsignal. The measurement section 305 can be composed of a measurementinstrument, a measurement circuit or a measurement apparatus describedbased on the common knowledge in the technical field according to thepresent disclosure.

For example, the measurement section 305 may perform Radio ResourceManagement (RRM) measurement or Channel State Information (CSI)measurement based on the received signal. The measurement section 305may measure received power (e.g., Reference Signal Received Power(RSRP)), received quality (e.g., Reference Signal Received Quality(RSRQ), a Signal to Interference plus Noise Ratio (SINR) or a Signal toNoise Ratio (SNR)), a signal strength (e.g., a Received Signal StrengthIndicator (RSSI)) or channel information (e.g., CSI). The measurementsection 305 may output a measurement result to the control section 301.

In addition, each transmitting/receiving section 103 may transmitconfiguration information (e.g., at least one of a CSI-MeasConfigInformation Element (IE), a CSI-ResourceConfig IE and a CSI-ReportConfigIE of RRC) related to measurement (or a measurement report or a report)for Channel State Information (CSI) to the user terminal 20. Eachtransmitting/receiving section 103 may receive the CSI transmitted fromthe user terminal 20.

In addition, each transmitting/receiving section 103 may transmitinformation (e.g., “beamselectioncriteria” or “reportQuantity” of RRC)related to a beam selection index to the user terminal 20. Eachtransmitting/receiving section 103 may receive the CSI transmitted fromthe user terminal 20.

The control section 301 may determine a beam used by the base station 10or the user terminal 20 based on the CSI (beam report) from the userterminal 20.

(User Terminal)

FIG. 10 is a diagram illustrating one example of an overallconfiguration of the user terminal according to the one embodiment. Theuser terminal 20 includes pluralities of transmission/reception antennas201, amplifying sections 202 and transmitting/receiving sections 203, abaseband signal processing section 204 and an application section 205.In this regard, the user terminal 20 only needs to be configured toinclude one or more of each of the transmission/reception antennas 201,the amplifying sections 202 and the transmitting/receiving sections 203.

Each amplifying section 202 amplifies a radio frequency signal receivedat each transmission/reception antenna 201. Each transmitting/receivingsection 203 receives a downlink signal amplified by each amplifyingsection 202. Each transmitting/receiving section 203 performs frequencyconversion on the received signal into a baseband signal, and outputsthe baseband signal to the baseband signal processing section 204. Thetransmitting/receiving sections 203 can be composed oftransmitters/receivers, transmission/reception circuits ortransmission/reception apparatuses described based on the commonknowledge in the technical field according to the present disclosure. Inthis regard, the transmitting/receiving sections 203 may be composed asan integrated transmitting/receiving section or may be composed oftransmission sections and reception sections.

The baseband signal processing section 204 performs FFT processing,error correcting decoding and retransmission control receptionprocessing on the input baseband signal. The baseband signal processingsection 204 transfers downlink user data to the application section 205.The application section 205 performs processing related to layers higherthan a physical layer and an MAC layer. Furthermore, the baseband signalprocessing section 204 may transfer broadcast information of thedownlink data, too, to the application section 205.

On the other hand, the application section 205 inputs uplink user datato the baseband signal processing section 204. The baseband signalprocessing section 204 performs retransmission control transmissionprocessing (e.g., HARQ transmission processing), channel coding,precoding, Discrete Fourier Transform (DFT) processing and IFFTprocessing on the uplink user data, and transfers the uplink user datato each transmitting/receiving section 203.

Each transmitting/receiving section 203 converts the baseband signaloutput from the baseband signal processing section 204 into a radiofrequency range, and transmits a radio frequency signal. The radiofrequency signal subjected to the frequency conversion by eachtransmitting/receiving section 203 is amplified by each amplifyingsection 202, and is transmitted from each transmission/reception antenna201.

FIG. 11 is a diagram illustrating one example of a functionconfiguration of the user terminal according to the one embodiment. Inaddition, this example mainly illustrates function blocks ofcharacteristic portions according to the present embodiment, and assumesthat the user terminal 20 includes other function blocks, too, that arenecessary for radio communication.

The baseband signal processing section 204 of the user terminal 20includes at least a control section 401, a transmission signalgenerating section 402, a mapping section 403, a received signalprocessing section 404 and a measurement section 405. In addition, thesecomponents only need to be included in the user terminal 20, and part orall of the components may not be included in the baseband signalprocessing section 204.

The control section 401 controls the entire user terminal 20. Thecontrol section 401 can be composed of a controller, a control circuitor a control apparatus described based on the common knowledge in thetechnical field according to the present disclosure.

The control section 401 controls, for example, signal generation of thetransmission signal generating section 402 and signal allocation of themapping section 403. Furthermore, the control section 401 controlssignal reception processing of the received signal processing section404 and signal measurement of the measurement section 405.

The control section 401 obtains from the received signal processingsection 404 a downlink control signal and a downlink data signaltransmitted from the base station 10. The control section 401 controlsgeneration of an uplink control signal and an uplink data signal basedon the downlink control signal as a result of deciding whether or not itis necessary to perform retransmission control on the downlink datasignal.

When obtaining from the received signal processing section 404 variouspieces of information notified from the base station 10, the controlsection 401 may update parameters used for control based on the variouspieces of information.

The transmission signal generating section 402 generates an uplinksignal (such as an uplink control signal, an uplink data signal or anuplink reference signal) based on an instruction from the controlsection 401, and outputs the uplink signal to the mapping section 403.The transmission signal generating section 402 can be composed of asignal generator, a signal generating circuit or a signal generatingapparatus described based on the common knowledge in the technical fieldaccording to the present disclosure.

The transmission signal generating section 402 generates, for example,an uplink control signal related to transmission acknowledgementinformation and Channel State Information (CSI) based on the instructionfrom the control section 401. Furthermore, the transmission signalgenerating section 402 generates an uplink data signal based on theinstruction from the control section 401. When, for example, thedownlink control signal notified from the base station 10 includes a ULgrant, the transmission signal generating section 402 is instructed bythe control section 401 to generate an uplink data signal.

The mapping section 403 maps the uplink signal generated by thetransmission signal generating section 402, on radio resources based onthe instruction from the control section 401, and outputs the uplinksignal to each transmitting/receiving section 203. The mapping section403 can be composed of a mapper, a mapping circuit or a mappingapparatus described based on the common knowledge in the technical fieldaccording to the present disclosure.

The received signal processing section 404 performs reception processing(e.g., demapping, demodulation and decoding) on the received signalinput from each transmitting/receiving section 203. In this regard, thereceived signal is, for example, a downlink signal (such as a downlinkcontrol signal, a downlink data signal or a downlink reference signal)transmitted from the base station 10. The received signal processingsection 404 can be composed of a signal processor, a signal processingcircuit or a signal processing apparatus described based on the commonknowledge in the technical field according to the present disclosure.Furthermore, the received signal processing section 404 can compose thereception section according to the present disclosure.

The received signal processing section 404 outputs information decodedby the reception processing to the control section 401. The receivedsignal processing section 404 outputs, for example, broadcastinformation, system information, an RRC signaling and DCI to the controlsection 401. Furthermore, the received signal processing section 404outputs at least one of the received signal and the signal after thereception processing to the measurement section 405.

The measurement section 405 performs measurement related to the receivedsignal. The measurement section 405 can be composed of a measurementinstrument, a measurement circuit or a measurement apparatus describedbased on the common knowledge in the technical field according to thepresent disclosure. The measurement section 405 may compose at leastpart of a reception section according to the present disclosure.

For example, the measurement section 405 may perform RRM measurement orCSI measurement based on the received signal. The measurement section405 may measure received power (e.g., RSRP), received quality (e.g.,RSRQ, an SINR or an SNR), a signal strength (e.g., RSSI) or channelinformation (e.g., CSI). The measurement section 405 may output ameasurement result to the control section 401.

In addition, each transmitting/receiving section 203 may receive theinformation (e.g., “beamselectioncriteria” or “reportQuantity” of RRC)related to the beam selection index. Each transmitting/receiving section203 may transmit CSI including information (such as L1-RSRP, L1interference power, L1-RSRQ or an L1-SINR) based on the abovemeasurement and related to an interference to the base station 10.

The control section 401 may select a beam based on an index indicated bythe information related to the above beam selection index.

The control section 401 may use configuration information (e.g.,“reportQuantity” of RRC) of a report quantity of the channel stateinformation as the information related to the beam selection index.

When a plurality of indices are indicated as the beam selection indices,the control section 401 may select first number (e.g., M) measurementresults based on one (e.g., L1-RSRP) of the indices, and further selectsecond number (e.g., “nrofReportedRS” of RRC) measurement results fromthe first number measurement results based on the other one (e.g., theL1-RSRQ or the L1-SINR) of the indices.

The control section 401 may control reporting of at least one of RSRQ(csi-RSRQ/ssb-RSRQ) and an SINR (csi-SINR/ssb-SINR) based on theconfiguration information (e.g., “reportQuantity” of RRC) of the reportquantity of the channel state information.

(Hardware Configuration)

In addition, the block diagrams used to describe the above embodimentsillustrate blocks in function units. These function blocks (components)are realized by an arbitrary combination of at least one of hardware andsoftware. Furthermore, a method for realizing each function block is notlimited in particular. That is, each function block may be realized byusing one physically or logically coupled apparatus or may be realizedby using a plurality of these apparatuses formed by connecting two ormore physically or logically separate apparatuses directly or indirectly(by using, for example, wired connection or radio connection). Eachfunction block may be realized by combining software with the above oneapparatus or a plurality of above apparatuses.

In this regard, the functions include judging, determining, deciding,calculating, computing, processing, deriving, investigating, looking up,ascertaining, receiving, transmitting, outputting, accessing, resolving,selecting, choosing, establishing, comparing, assuming, expecting,considering, broadcasting, notifying, communicating, forwarding,configuring, reconfiguring, allocating, mapping, and assigning, yet arenot limited to these. For example, a function block (component) thatcauses transmission to function may be referred to as a transmittingunit or a transmitter. As described above, the method for realizing eachfunction block is not limited in particular.

For example, the base station and the user terminal according to the oneembodiment of the present disclosure may function as computers thatperform processing of the radio communication method according to thepresent disclosure. FIG. 12 is a diagram illustrating one example of thehardware configurations of the base station and the user terminalaccording to the one embodiment. The above-described base station 10 anduser terminal 20 may be each physically configured as a computerapparatus that includes a processor 1001, a memory 1002, a storage 1003,a communication apparatus 1004, an input apparatus 1005, an outputapparatus 1006 and a bus 1007.

In this regard, a word “apparatus” in the following description can beread as a circuit, a device or a unit. The hardware configurations ofthe base station 10 and the user terminal 20 may be configured toinclude one or a plurality of apparatuses illustrated in FIG. 12 or maybe configured without including part of the apparatuses.

For example, FIG. 12 illustrates the only one processor 1001. However,there may be a plurality of processors. Furthermore, processing may beexecuted by 1 processor or processing may be executed by 2 or moreprocessors concurrently or successively or by using another method. Inaddition, the processor 1001 may be implemented by 1 or more chips.

Each function of the base station 10 and the user terminal 20 isrealized by, for example, causing hardware such as the processor 1001and the memory 1002 to read given software (program), and therebycausing the processor 1001 to perform an operation, and controlcommunication via the communication apparatus 1004 and control at leastone of reading and writing of data in the memory 1002 and the storage1003.

The processor 1001 causes, for example, an operating system to operateto control the entire computer. The processor 1001 may be composed of aCentral Processing Unit (CPU) including an interface for a peripheralapparatus, a control apparatus, an operation apparatus and a register.For example, the above-described baseband signal processing section 104(204) and call processing section 105 may be realized by the processor1001.

Furthermore, the processor 1001 reads programs (program codes), asoftware module or data from at least one of the storage 1003 and thecommunication apparatus 1004 out to the memory 1002, and executesvarious types of processing according to these programs, software moduleor data. As the programs, programs that cause the computer to execute atleast part of the operations described in the above-describedembodiments are used. For example, the control section 401 of the userterminal 20 may be realized by a control program that is stored in thememory 1002 and operates on the processor 1001, and other functionblocks may be also realized likewise.

The memory 1002 is a computer-readable recording medium, and may becomposed of at least one of, for example, a Read Only Memory (ROM), anErasable Programmable ROM (EPROM), an Electrically EPROM (EEPROM), aRandom Access Memory (RAM) and other appropriate storage media. Thememory 1002 may be referred to as a register, a cache or a main memory(main storage apparatus). The memory 1002 can store programs (programcodes) and a software module that can be executed to perform the radiocommunication method according to the one embodiment of the presentdisclosure.

The storage 1003 is a computer-readable recording medium, and may becomposed of at least one of, for example, a flexible disk, a floppy(registered trademark) disk, a magnetooptical disk (e.g., a compact disk(Compact Disc ROM (CD-ROM)), a digital versatile disk and a Blu-ray(registered trademark) disk), a removable disk, a hard disk drive, asmart card, a flash memory device (e.g., a card, a stick or a keydrive), a magnetic stripe, a database, a server and other appropriatestorage media. The storage 1003 may be referred to as an auxiliarystorage apparatus.

The communication apparatus 1004 is hardware (transmission/receptiondevice) that performs communication between computers via at least oneof a wired network and a radio network, and is also referred to as, forexample, a network device, a network controller, a network card and acommunication module. The communication apparatus 1004 may be configuredto include a high frequency switch, a duplexer, a filter and a frequencysynthesizer to realize at least one of, for example, Frequency DivisionDuplex (FDD) and Time Division Duplex (TDD). For example, theabove-described transmission/reception antennas 101 (201), amplifyingsections 102 (202), transmitting/receiving sections 103 (203) andcommunication path interface 106 may be realized by the communicationapparatus 1004. Each transmitting/receiving section 103 may bephysically or logically separately implemented as a transmission section103 a and a reception section 103 b.

The input apparatus 1005 is an input device (e.g., a keyboard, a mouse,a microphone, a switch, a button or a sensor) that accepts an input froman outside. The output apparatus 1006 is an output device (e.g., adisplay, a speaker or a Light Emitting Diode (LED) lamp) that sends anoutput to the outside. In addition, the input apparatus 1005 and theoutput apparatus 1006 may be an integrated component (e.g., touchpanel).

Furthermore, each apparatus such as the processor 1001 or the memory1002 is connected by the bus 1007 that communicates information. The bus1007 may be composed by using a single bus or may be composed by usingdifferent buses between apparatuses.

Furthermore, the base station 10 and the user terminal 20 may beconfigured to include hardware such as a microprocessor, a DigitalSignal Processor (DSP), an Application Specific Integrated Circuit(ASIC), a Programmable Logic Device (PLD) and a Field Programmable GateArray (FPGA). The hardware may be used to realize part or entirety ofeach function block. For example, the processor 1001 may be implementedby using at least one of these types of hardware.

Modified Example

In addition, each term that has been described in the present disclosureand each term that is necessary to understand the present disclosure maybe replaced with terms having identical or similar meanings. Forexample, at least one of a channel and a symbol may be a signal(signaling). Furthermore, a signal may be a message. A reference signalcan be also abbreviated as an RS (Reference Signal), or may be referredto as a pilot or a pilot signal depending on standards to be applied.Furthermore, a Component Carrier (CC) may be referred to as a cell, afrequency carrier and a carrier frequency.

A radio frame may include one or a plurality of durations (frames) in atime domain. Each of one or a plurality of durations (frames) thatcomposes a radio frame may be referred to as a subframe. Furthermore,the subframe may include one or a plurality of slots in the time domain.The subframe may be a fixed time duration (e.g., 1 ms) that does notdepend on the numerologies.

In this regard, the numerology may be a communication parameter to beapplied to at least one of transmission and reception of a certainsignal or channel. The numerology may indicate at least one of, forexample, a SubCarrier Spacing (SCS), a bandwidth, a symbol length, acyclic prefix length, a Transmission Time Interval (TTI), the number ofsymbols per TTI, a radio frame configuration, specific filteringprocessing performed by a transceiver in a frequency domain, andspecific windowing processing performed by the transceiver in a timedomain.

The slot may include one or a plurality of symbols (Orthogonal FrequencyDivision Multiplexing (OFDM) symbols or Single Carrier-FrequencyDivision Multiple Access (SC-FDMA) symbols) in the time domain.Furthermore, the slot may be a time unit based on the numerologies.

The slot may include a plurality of mini slots. Each mini slot mayinclude one or a plurality of symbols in the time domain. Furthermore,the mini slot may be referred to as a subslot. The mini slot may includea smaller number of symbols than those of the slot. The PDSCH (or thePUSCH) to be transmitted in larger time units than that of the mini slotmay be referred to as a PDSCH (PUSCH) mapping type A. The PDSCH (or thePUSCH) to be transmitted by using the mini slot may be referred to as aPDSCH (PUSCH) mapping type B.

The radio frame, the subframe, the slot, the mini slot and the symboleach indicate a time unit for conveying signals. The other correspondingnames may be used for the radio frame, the subframe, the slot, the minislot and the symbol. In addition, time units such as a frame, asubframe, a slot, a mini slot and a symbol in the present disclosure maybe interchangeably read.

For example, 1 subframe may be referred to as a Transmission TimeInterval (TTI), a plurality of contiguous subframes may be referred toas TTIs, or 1 slot or 1 mini slot may be referred to as a TTI. That is,at least one of the subframe and the TTI may be a subframe (1 ms)according to legacy LTE, may be a duration (e.g., 1 to 13 symbols)shorter than 1 ms or may be a duration longer than 1 ms. In addition, aunit that indicates the TTI may be referred to as a slot or a mini slotinstead of a subframe.

In this regard, the TTI refers to, for example, a minimum time unit ofscheduling of radio communication. For example, in the LTE system, thebase station performs scheduling for allocating radio resources (afrequency bandwidth or transmission power that can be used in each userterminal) in TTI units to each user terminal. In this regard, adefinition of the TTI is not limited to this.

The TTI may be a transmission time unit of a channel-coded data packet(transport block), code block or codeword, or may be a processing unitof scheduling or link adaptation. In addition, when the TTI is given, atime period (e.g., the number of symbols) in which a transport block, acode block or a codeword is actually mapped may be shorter than the TTI.

In addition, when 1 slot or 1 mini slot is referred to as a TTI, 1 ormore TTIs (i.e., 1 or more slots or 1 or more mini slots) may be aminimum time unit of scheduling. Furthermore, the number of slots (thenumber of mini slots) that compose a minimum time unit of the schedulingmay be controlled.

The TTI having the time duration of 1 ms may be referred to as a generalTTI (TTIs according to LTE Rel. 8 to 12), a normal TTI, a long TTI, ageneral subframe, a normal subframe, a long subframe or a slot. A TTIshorter than the general TTI may be referred to as a reduced TTI, ashort TTI, a partial or fractional TTI, a reduced subframe, a shortsubframe, a mini slot, a subslot or a slot.

In addition, the long TTI (e.g., the general TTI or the subframe) may beread as a TTI having a time duration exceeding 1 ms, and the short TTI(e.g., the reduced TTI) may be read as a TTI having a TTI length lessthan the TTI length of the long TTI and equal to or more than 1 ms.

A Resource Block (RB) is a resource allocation unit of the time domainand the frequency domain, and may include one or a plurality ofcontiguous subcarriers in the frequency domain. The numbers ofsubcarriers included in RBs may be the same irrespectively of anumerology, and may be, for example, 12. The numbers of subcarriersincluded in the RBs may be determined based on the numerology.

Furthermore, the RB may include one or a plurality of symbols in thetime domain or may have the length of 1 slot, 1 mini slot, 1 subframe or1 TTI. 1 TTI or 1 subframe may each include one or a plurality ofresource blocks.

In this regard, one or a plurality of RBs may be referred to as aPhysical Resource Block (PRB: Physical RB), a Sub-Carrier Group (SCG), aResource Element Group (REG), a PRB pair or an RB pair.

Furthermore, the resource block may include one or a plurality ofResource Elements (REs). For example, 1 RE may be a radio resourcedomain of 1 subcarrier and 1 symbol.

A Bandwidth Part (BWP) (that may be referred to as a partial bandwidth)may mean a subset of contiguous common Resource Blocks (common RBs) fora certain numerology in a certain carrier. In this regard, the common RBmay be specified by an RB index based on a common reference point of thecertain carrier. A PRB may be defined based on a certain BWP, and may benumbered in the certain BWP.

The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). Oneor a plurality of BWPs in 1 carrier may be configured to the UE.

At least one of the configured BWPs may be active, and the UE may notassume that a given signal/channel is transmitted and received outsidethe active BWP. In addition, a “cell” and a “carrier” in the presentdisclosure may be read as a “BWP”.

In this regard, structures of the above-described radio frame, subframe,slot, mini slot and symbol are only exemplary structures. For example,configurations such as the number of subframes included in a radioframe, the number of slots per subframe or radio frame, the number ofmini slots included in a slot, the numbers of symbols and RBs includedin a slot or a mini slot, the number of subcarriers included in an RB,the number of symbols in a TTI, a symbol length and a Cyclic Prefix (CP)length can be variously changed.

Furthermore, the information and the parameters described in the presentdisclosure may be expressed by using absolute values, may be expressedby using relative values with respect to given values or may beexpressed by using other corresponding information. For example, a radioresource may be instructed by a given index.

Names used for parameters in the present disclosure are in no respectrestrictive names. Furthermore, numerical expressions that use theseparameters may be different from those explicitly disclosed in thepresent disclosure. Various channels (the Physical Uplink ControlChannel (PUCCH) and the Physical Downlink Control Channel (PDCCH)) andinformation elements can be identified based on various suitable names.Therefore, various names assigned to these various channels andinformation elements are in no respect restrictive names.

The information and the signals described in the present disclosure maybe expressed by using one of various different techniques. For example,the data, the instructions, the commands, the information, the signals,the bits, the symbols and the chips mentioned in the above entiredescription may be expressed as voltages, currents, electromagneticwaves, magnetic fields or magnetic particles, optical fields or photons,or arbitrary combinations of these.

Furthermore, the information and the signals can be output at least oneof from a higher layer to a lower layer and from the lower layer to thehigher layer. The information and the signals may be input and outputvia a plurality of network nodes.

The input and output information and signals may be stored in a specificlocation (e.g., memory) or may be managed by using a management table.The information and signals to be input and output can be overridden,updated or additionally written. The output information and signals maybe deleted. The input information and signals may be transmitted toother apparatuses.

Notification of information is not limited to the aspect/embodimentsdescribed in the present disclosure and may be performed by using othermethods. For example, the information may be notified by a physicallayer signaling (e.g., Downlink Control Information (DCI) and UplinkControl Information (UCI)), a higher layer signaling (e.g., a RadioResource Control (RRC) signaling, broadcast information (a MasterInformation Block (MIB) and a System Information Block (SIB)), and aMedium Access Control (MAC) signaling), other signals or combinations ofthese.

In addition, the physical layer signaling may be referred to as Layer1/Layer 2 (L1/L2) control information (L1/L2 control signal) or L1control information (L1 control signal). Furthermore, the RRC signalingmay be referred to as an RRC message, and may be, for example, anRRCConnectionSetup message or an RRCConnectionReconfiguration message.Furthermore, the MAC signaling may be notified by using, for example, anMAC Control Element (MAC CE).

Furthermore, notification of given information (e.g., notification of“being X”) is not limited to explicit notification, and may be givenimplicitly (by, for example, not giving notification of the giveninformation or by giving notification of another information). Decisionmay be made based on a value (0 or 1) expressed as 1 bit, may be madebased on a boolean expressed as true or false or may be made bycomparing numerical values (by, for example, making comparison with agiven value).

Irrespectively of whether software is referred to as software, firmware,middleware, a microcode or a hardware description language or isreferred to as other names, the software should be widely interpreted tomean a command, a command set, a code, a code segment, a program code, aprogram, a subprogram, a software module, an application, a softwareapplication, a software package, a routine, a subroutine, an object, anexecutable file, an execution thread, a procedure or a function.

Furthermore, software, commands and information may be transmitted andreceived via transmission media. When, for example, the software istransmitted from websites, servers or other remote sources by using atleast ones of wired techniques (e.g., coaxial cables, optical fibercables, twisted pairs and Digital Subscriber Lines (DSLs)) and radiotechniques (e.g., infrared rays and microwaves), at least ones of thesewired techniques and radio techniques are included in a definition ofthe transmission media.

The terms “system” and “network” used in the present disclosure can beinterchangeably used.

In the present disclosure, terms such as “precoding”, a “precoder”, a“weight (precoding weight)”, “Quasi-Co-Location (QCL)”, a “TransmissionConfiguration Indication state (TCI state)”, a “spatial relation”, a“spatial domain filter”, “transmission power”, “phase rotation”, an“antenna port”, an “antenna port group”, a “layer”, “the number oflayers”, a “rank”, a “resource”, a “beam”, a “beam width”, a “beamangle”, an “antenna”, an “antenna element” and a panel” can beinterchangeably used.

In the present disclosure, terms such as a “base Station (BS)”, a “radiobase station”, a “fixed station”, a “NodeB”, an “eNodeB (eNB)”, a“gNodeB (gNB)”, an “access point”, a “Transmission Point (TP)”, a“Reception Point (RP)”, a “Transmission/Reception Point (TRP)”, a“panel”, a “cell”, a “sector”, a “cell group”, a “carrier” and a“component carrier” can be interchangeably used. The base station isalso referred to as terms such as a macro cell, a small cell, afemtocell or a picocell.

The base station can accommodate one or a plurality of (e.g., three)cells. When the base station accommodates a plurality of cells, anentire coverage area of the base station can be partitioned into aplurality of smaller areas. Each smaller area can also provide acommunication service via a base station subsystem (e.g., indoor smallbase station (RRH: Remote Radio Head)). The term “cell” or “sector”indicates part or the entirety of the coverage area of at least one ofthe base station and the base station subsystem that provide acommunication service in this coverage.

In the present disclosure, the terms such as “Mobile Station (MS)”,“user terminal”, “user apparatus (UE: User Equipment)” and “terminal”can be interchangeably used.

The mobile station is also referred to as a subscriber station, a mobileunit, a subscriber unit, a wireless unit, a remote unit, a mobiledevice, a wireless device, a wireless communication device, a remotedevice, a mobile subscriber station, an access terminal, a mobileterminal, a wireless terminal, a remote terminal, a handset, a useragent, a mobile client, a client or some other appropriate terms in somecases.

At least one of the base station and the mobile station may be referredto as a transmission apparatus, a reception apparatus or a communicationapparatus. In addition, at least one of the base station and the mobilestation may be a device mounted on a movable body or the movable bodyitself. The movable body may be a vehicle (e.g., a car or an airplane),may be a movable body (e.g., a drone or a self-driving car) that movesunmanned or may be a robot (a manned type or an unmanned type). Inaddition, at least one of the base station and the mobile stationincludes an apparatus, too, that does not necessarily move during acommunication operation. For example, at least one of the base stationand the mobile station may be an Internet of Things (loT) device such asa sensor.

Furthermore, the base station in the present disclosure may be read asthe user terminal. For example, each aspect/embodiment of the presentdisclosure may be applied to a configuration where communication betweenthe base station and the user terminal is replaced with communicationbetween a plurality of user terminals (that may be referred to as, forexample, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In thiscase, the user terminal 20 may be configured to include the functions ofthe above-described base station 10. Furthermore, words such as “uplink”and “downlink” may be read as a word (e.g., a “side”) that matchesterminal-to-terminal communication. For example, the uplink channel andthe downlink channel may be read as side channels.

Similarly, the user terminal in the present disclosure may be read asthe base station. In this case, the base station 10 may be configured toinclude the functions of the above-described user terminal 20.

In the present disclosure, operations performed by the base station areperformed by an upper node of this base station depending on cases.Obviously, in a network including one or a plurality of network nodesincluding the base stations, various operations performed to communicatewith a terminal can be performed by base stations, one or more networknodes (that are regarded as, for example, Mobility Management Entities(MMEs) or Serving-Gateways (S-GWs), yet are not limited to these) otherthan the base stations or a combination of these.

Each aspect/embodiment described in the present disclosure may be usedalone, may be used in combination or may be switched and used whencarried out. Furthermore, orders of the processing procedures, thesequences and the flowchart according to each aspect/embodimentdescribed in the present disclosure may be rearranged unlesscontradictions arise. For example, the method described in the presentdisclosure presents various step elements by using an exemplary orderand is not limited to the presented specific order.

Each aspect/embodiment described in the present disclosure may beapplied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond(LTE-B), SUPER 3G, IMT-Advanced, the 4th generation mobile communicationsystem (4G), the 5th generation mobile communication system (5G), FutureRadio Access (FRA), the New Radio Access Technology (New-RAT), New Radio(NR), New radio access (NX), Future generation radio access (FX), GlobalSystem for Mobile communications (GSM) (registered trademark), CDMA2000,Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registeredtrademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20,Ultra-WideBand (UWB), Bluetooth (registered trademark), systems that useother appropriate radio communication methods, or next-generationsystems that are expanded based on these systems. Furthermore, aplurality of systems may be combined (e.g., a combination of LTE orLTE-A and 5G) and applied.

The phrase “based on” used in the present disclosure does not mean“based only on” unless specified otherwise. In other words, the phrase“based on” means both of “based only on” and “based at least on”.

Every reference to elements that use names such as “first” and “second”used in the present disclosure does not generally limit the quantity orthe order of these elements. These names can be used in the presentdisclosure as a convenient method for distinguishing between two or moreelements. Hence, the reference to the first and second elements does notmean that only two elements can be employed or the first element shouldprecede the second element in some way.

The term “deciding (determining)” used in the present disclosureincludes diverse operations in some cases. For example, “deciding(determining)” may be regarded to “decide (determine)” judging,calculating, computing, processing, deriving, investigating, looking up,search and inquiry (e.g., looking up in a table, a database or anotherdata structure), and ascertaining.

Furthermore, “deciding (determining)” may be regarded to “decide(determine)” receiving (e.g., receiving information), transmitting(e.g., transmitting information), input, output and accessing (e.g.,accessing data in a memory).

Furthermore, “deciding (determining)” may be regarded to “decide(determine)” resolving, selecting, choosing, establishing and comparing.That is, “deciding (determining)” may be regarded to “decide(determine)” some operation.

Furthermore, “deciding (determining)” may be read as “assuming”,“expecting” and “considering”.

The words “connected” and “coupled” used in the present disclosure orevery modification of these words can mean every direct or indirectconnection or coupling between 2 or more elements, and can include that1 or more intermediate elements exist between the two elements“connected” or “coupled” with each other. The elements may be coupled orconnected physically or logically or by a combination of these physicaland logical connections. For example, “connection” may be read as“access”.

It can be understood in the present disclosure that, when connected, thetwo elements are “connected” or “coupled” with each other by using 1 ormore electric wires, cables or printed electrical connection, and byusing electromagnetic energy having wavelengths in radio frequencydomains, microwave domains or (both of visible and invisible) lightdomains in some non-restrictive and non-comprehensive examples.

A sentence that “A and B are different” in the present disclosure maymean that “A and B are different from each other”. In this regard, thesentence may mean that “A and B are each different from C”. Words suchas “separate” and “coupled” may be also interpreted in a similar way to“different”.

When the words “include” and “including” and modifications of thesewords are used in the present disclosure, these words intend to becomprehensive similar to the word “comprising”. Furthermore, the word“or” used in the present disclosure intends not to be an exclusive OR.

When, for example, translation adds articles such as a, an and the inEnglish in the present disclosure, the present disclosure may includethat nouns coming after these articles are plural.

The invention according to the present disclosure has been described indetail above. However, it is obvious for a person skilled in the artthat the invention according to the present disclosure is not limited tothe embodiments described in the present disclosure. The inventionaccording to the present disclosure can be carried out as modified andchanged aspects without departing from the gist and the scope of theinvention defined based on the recitation of the claims. Accordingly,the description of the present disclosure is intended for exemplaryexplanation, and does not bring any restrictive meaning to the inventionaccording to the present disclosure.

1. A user terminal comprising: a reception section that receivesinformation related to a beam selection index; and a control sectionthat selects a beam based on an index indicated by the information. 2.The user terminal according to claim 1, wherein the control section usesconfiguration information of a report quantity of channel stateinformation as the information.
 3. The user terminal according to claim1, wherein, when a plurality of indices are indicated as the beamselection indices, the control section selects first number measurementresults based on one of the indices, and further selects second numbermeasurement results from the first number measurement results based onother one of the indices.
 4. The user terminal according to claim 1,wherein the control section controls reporting of at least one ofReference Signal Received Quality (RSRQ) and a Signal to Interferenceplus Noise Ratio (SINR) based on configuration information of a reportquantity of channel state information.
 5. A radio communication methodof a user terminal comprising: receiving information related to a beamselection index; and selecting a beam based on an index indicated by theinformation.
 6. The user terminal according to claim 2, wherein, when aplurality of indices are indicated as the beam selection indices, thecontrol section selects first number measurement results based on one ofthe indices, and further selects second number measurement results fromthe first number measurement results based on other one of the indices.7. The user terminal according to claim 2, wherein the control sectioncontrols reporting of at least one of Reference Signal Received Quality(RSRQ) and a Signal to Interference plus Noise Ratio (SINR) based onconfiguration information of a report quantity of channel stateinformation.
 8. The user terminal according to claim 3, wherein thecontrol section controls reporting of at least one of Reference SignalReceived Quality (RSRQ) and a Signal to Interference plus Noise Ratio(SINR) based on configuration information of a report quantity ofchannel state information.